Magnetron sputter devices are characterized by crossed electric and magnetic fields in an evacuated chamber into which an inert, ionizable gas, such as argon, is introduced. The gas is ionized by the electric field. The magnetic field confines the ionized gas, which forms a plasma, in proximity to a target structure which emits atoms that are incident on a workpiece; typically a substrate in a coating process. Generally, the magnetic field is established by a permanent magnet structure, although increasingly electromagnetic devices are being employed for this purpose. In coating applications, the magnetron sputtering devices are frequently employed to deposit metals in the manufacture of electronic, integrated circuit type devices. It is also known to deposit magnetic materials in the manufacture of high density magnetic discs of a type used for magnetic disc memories.
In prior art magnetron sputtering devices, uniform coating thickness across a substrate was obtained by moving the substrates during coating. Moving the substrates also assisted in obtaining step coverage, i.e., conformal coating over step type transitions. Of course there are many problems in moving a substrate during operation of a sputtering device. It is also desirable in certain instances to co-deposit different materials, particularly materials which are difficult or impossible to alloy; thus, materials which are not adapted to being formed as a single target. In the past co-depositing has been performed by moving a substrate relative to several targets, each having a planar configuration. In all instances, it is desirable to operate the sputtering device at as high a rate as possible.
It is desirable for magnetron cathode sputtering devices to be as compact and as light weight as possible. Magnetic flux is more efficiently coupled to targets if the sputter device, particularly the cathode assembly of the sputter device, is maintained compact. Minimizing the volume and weight of the device assists in reducing the costs thereof.
It is, accordingly, an object of the present invention to provide a new and improved magnetron sputtering device wherein material emitted from a relatively large target area is incident uniformly on a large area workpiece.
Another object of the invention is to provide a magnetron sputtering device having relatively high speed operating rate and which is relatively efficient.
An additional object of the invention is to provide a new and improved magnetron sputtering device that is relatively compact, light weight, highly efficient and relatively low cost.